Adjustable/lockable safety-selector switch for AR15/M16 style firearms

ABSTRACT

A device is provided to securely solve the safety problem when tolerance stack up is present so that the AR15/M16 style firearm will not fire or allow unsafe movement of the trigger components when the safety-selector switch is in the “safe” position. The device is mounted to the safety-selector switch, uses a plurality of adjustment set screws and locking screws, with the number varying upon the safety-selector switch being for an AR15, an M16, or a left, right, or ambidextrous model AR15/M16 style firearm, and being a semi-auto or selective-fire version of the AR15/M16 firearm.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an adjustable/lockable safety-selectorswitch for AR-15/M-16 style firearms, and more particularly to asafety-selector switch for right hand, left hand, ambidextrous andselect fire AR15/M16 style firearms as well as standard and oversizeselectors/levers and single and two-stage trigger groups for AR15/M16style firearms.

2. Description of the Prior Art

Mass production of parts and assembly-line style installation of partsoften leads to a combination of tolerances being added together, andthis is commonly referred to as “tolerance stack up”. In the case oftrigger parts and mechanisms, tolerance stack up can lead to a dangerousfirearm, a firearm that can fire or nearly fire when the safety-selectorswitch is in the “safe” position.

This is especially a problem with the AR15/M16 style firearm because thesafety-selector switch or lever enters the receiver of the firearmthrough a hole of a specific size. This means that the diameter of thesafety-selector switch's cross shaft is limited by the size of the lowerreceiver's entry hole.

The cross shaft is the part of the safety-selector switch that isdesigned to block component movement in the trigger group when thesafety-selector switch is in the “safe” position, thus locking andblocking the trigger group components in a safely engaged condition.This should mean that the hammer and sear are blocked in a conditionwith a safe and functional amount of contact or engagement between thetwo parts when the hammer is in its cocked position.

When the safety-selector switch is moved to the “fire” position, thereis room for the trigger components to move out of their engagedposition, thus allowing the hammer to fall and the firearm to dischargethe cartridge in the chamber when the trigger is pulled. This isaccomplished via a recess machined into the safety selector's crossshaft. This recess allows trigger component movement when the selectoris in the “fire” position. Safety problems occur when tolerance stack upis present and the trigger components are allowed to move out of, ornearly out of their safely engaged, blocked position when the safety is“on”.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a device to securely solvethe safety problem when tolerance stack up is present so that theAR15/M16 style firearm will not for fire or allow unsafe movement of thetrigger components when the safety-selector switch is in the “safe”position.

In a preferred embodiment, the above object is achieved with theembodiment being mounted to the safety-selector switch of the AR15/M16style firearm. The embodiment uses a plurality of adjustment set screwsand locking screws, with the number of set screws and locking screwsvarying depending upon if the safety-selector switch is for an AR15, anM16, or a left hand, a right hand, or an ambidextrous model AR15/M16style firearm. The number of set screws and locking screws also variesdepending upon whether or not the firearm is a semi-auto or aselective-fire version of the AR15/M16 firearm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a safety-selector switch for an AR15 rifleshowing the adjustment and locking screws.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a safety-selector switch 1 for an AR-15 typefirearm and lock screws 2 and 3 and adjustment set screws 4 and 5 lockscrews are shown. Two threaded holes 7 and 8 are positioned in the crossshaft 6 of the safety-selector switch. The cross shaft 6 has twothreaded holes 9 and 10 (only 9 is shown in the drawing) positioned oneach end of the safety-selector switch.

The adjustment set screws 4 and 5 are threaded vertically into twothreaded holes 7 and 8 in the cross shaft 6 of the safety-selectorswitch 1. When the safety-selector switch 1 is in the “safe” position,these adjustment set screws 4 and 5 may be screwed out from the bottom,or six o'clock position on the cross shaft, to effectively take up anytolerance stack up.

The adjustment set screws 4 and 5 can be adjusted to bear against thetrigger tail and effectively block the movement of the hammer and sear,thus greatly increasing the safety-selector switch's effectiveness inthe “safe” position. The adjustability allows for the proper fitting ofthe safety-selector switch to the trigger tail, thus increasing themechanical safety of the trigger group, and in turn increases themechanical safety of the firearm.

Once the adjustment set screws 4 and 5 have been adjusted to properlyand safely interact with the trigger group, the adjustment setting maybe locked into position. This is accomplished by screwing lock setscrews 2 and 3 into the two small holes 9 and 10 into thesafety-selector switch horizontally from the three o'clock and nineo'clock positions, otherwise known as the ends of the horizontal crossshaft 6.

Locking set screws 2 and 3 from each end of the shaft are threaded intothe two threaded small holes 9 and 10 to bear against the verticaladjustment set screws 4 and 5. This effectively locks them into theirproperly adjusted positions. Industrial thread locking compounds mayalso be used to ensure that the locking set screws 2 and 3 are securedeven further, yet still allow the components to be later disassembled asneeded.

Due to there being multiple different forms of safety-selector switchescurrently being used with AR15/M16 style firearms, the number ofadjustment set screws and locking set screws required will vary. Thesafety-selector switch for the semi-auto AR15 that uses a lever forright-handed shooters utilizes four set screws. There are two adjustmentset screws that are positioned parallel to the flat on the cross shaft.The two holes for these adjustment set screws are drilled and tapped forthe adjustment set screws all the way through the cross shaft. The twolocking set screws are positioned horizontally at the three o'clock andnine o'clock positions on the cross shaft and the two holes for theselocking set screws are drilled and tapped so that they interface withthe two vertical holes for the adjustment set screws. This results inthe adjustment set screws being adjusted and then the locking set screwsbeing fixed to ensure that the adjustment set screws are locked andsecured in position.

The safety-selector switch for left handed shooters and ambidextroussafety-selector switches use only two set screws. One adjustment setscrew is used to block the hammer and sear into their position ofmaximum engagement while one locking set screw is used to lock theadjustment set screw into its properly adjusted position. Four setscrews are not used because the right side of the cross-shaft isoccupied by the left-handed lever and its shaft attachment

Select fire safety-selector switch levers generally use two set screws.One adjustment set screw is used to block the hammer and the sear intheir position of maximum engagement when the safety is on. One lockingset screw is used to lock the setting on the adjustment set screw.Because of the different contour of the select fire cross-shaft, thepositioning of four set screws is not possible.

While the invention has been shown and described with reference to acertain specific preferred embodiment, modification may now suggestitself to those skilled in the art. Such modifications and variouschanges in form and detail may be made herein without departing from thespirit and scope of the invention. Accordingly, it is understood thatthe invention will be limited only by the appended claims.

1. An improved safety selector switch for a AR-15 type or derivativefirearm, the selector switch comprising: (a) a safety selector switchwith a cross shaft and a lever; (b) at least one bore hole positionedthrough said cross shaft; (c) at least one adjustment screw to interfacewith said at least one bore hole; (d) at least one bore hole positionedon the safety selector switch at the end of said cross shaft; (e) atleast one locking screw to interface with said bore hole on the end ofsaid cross shaft; and (f) at least one locking screw interfacing with atleast one adjustment screw when adjustment screw is positioned in thecross shaft, and whereby when said the safety selector switch isassembled in an AR-15 type or derivative firearm and positioned so thatwhen the switch is in the safe position, the at least one bore holepositioned through said cross shaft is positioned at the six o'clockposition on said cross shaft, and whereby the at least one adjustmentscrew is positioned in said at least one bore hole to interface with thetrigger tail of said firearm, thus preventing movement of the hammer andsear of said firearm when said safety selector switch is in the safeposition, and whereby said at least one locking screw interfaces withsaid at least one adjustment screw to lock said at least one adjustmentscrew in position in said cross shaft of the safety selector switch. 2.The improved safety selector switch as claimed for in claim 1 wherebysaid safety selector switch is intended for use with right-handedshooters, and whereby said number of adjustment screws and correspondingbore holes positioned through said cross shaft of said safety selectorswitch is two, and whereby said number of locking screws andcorresponding bore holes positioned on the safety selector switch at theend of said cross shaft is two.
 3. The improved safety selector switchas claimed for in claim 1 whereby said safety selector switch isintended for use with left-handed shooters, and whereby said safetyselector switch uses one adjustment screw and corresponding bore holepositioned through said cross shaft and one locking screw andcorresponding bore hole positioned on the safety selector switch at theend of said cross shaft.
 4. The improved safety selector switch asclaimed for in claim 1 whereby said safety selector switch is anambidextrous safety selector switch, said ambidextrous safety selectorswitch comprising an additional lever and shaft attachment screw forattachment of said additional lever to said cross shaft, and wherebysaid safety selector switch uses one adjustment screw and correspondingbore hole positioned through said cross shaft and one locking screw andcorresponding bore hole positioned on the safety selector switch at theend of said cross shaft.
 5. The improved safety selector switch asclaimed for in claim 1 whereby said derivative firearm is an M16, M16A1,M16A2, or M16A4 rifle or derivative there from and whereby said safetyselector switch uses one adjustment screw and corresponding bore holepositioned through said cross shaft and one locking screw andcorresponding bore hole positioned on the safety selector switch at theend of said cross shaft.
 6. The improved safety selector switch asclaimed for in claim 1 whereby said derivative firearm is an M4, M4A1,or M4A2 carbine or derivative there from and whereby said safetyselector switch uses one adjustment screw and corresponding bore holepositioned through said cross shaft and one locking screw andcorresponding bore hole positioned on the safety selector switch at theend of said cross shaft.
 7. The improved safety selector switch asclaimed for in claim 4 whereby said derivative firearm is an M16, M16A1,M16A2, or M16A4 rifle or derivative there from.
 8. The improved safetyselector switch as claimed for in claim 4 whereby said derivativefirearm is an M4, M4A1, or M4A2 carbine or derivative there from.